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ddahlen

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The Asteroid Spin Barrier

dahlend.github.io
3 points·by ddahlen·10 months ago·0 comments

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ddahlen
·27 days ago·discuss
You can put in a public comment on these changes here:

https://www.federalregister.gov/documents/2026/05/29/2026-10...
ddahlen
·last month·discuss
I am a researcher studying orbital dynamics of asteroids/comets/dust. I made a very precise visualization tool for the solar system, it shows the motion of all of the known asteroids. When you click on a specific asteroid it will then show the hyper precise orbit for it which matches JPL's orbit calculations (full physics, n-body, relativity, non-spherical planets).

Not mobile friendly

https://dahlend.github.io/ketev/
ddahlen
·2 months ago·discuss
Research grade orbital mechanics, specifically of asteroids/comets. I've been working on it for 4 years now, finally tried using some AI tooling the last few months and ended up vibe coding a fun little visualization.

(Desktop Strongly recommended) https://dahlend.github.io/ketev/
ddahlen
·9 months ago·discuss
I suggest the appendix of the arxiv paper if you want to see some of the math required for solar system objects beyond simple Newtonian gravity (like Relativity corrections). I wrote that section specifically because I found it a pain in the ass to source those equations in literature.
ddahlen
·9 months ago·discuss
Its an implementation of a pretty standard integrator used by astronomers informally called "RADAU", but it is not exactly the same RADAU you would find elsewhere. Basically it is about as good as you can typically get for multi-step integrators, tuned for speed not precision though.

Note that how the code is laid out you cant really simulate non-solar system masses. Its really aimed at massless objects in the solar system, your 3-body simulations are actually quite difficult to do given the design.
ddahlen
·9 months ago·discuss
Working on orbital dynamics code for my PhD in astronomy, written in rust, it can accurately calculate the positions of all asteroids/comets to within a few meters. Today I am adding a new numerical integration method which should enable me to predict orbits from observations.

https://github.com/dahlend/kete

I'm working on modeling the motion of observed dust particles coming off of comet 67P, here is are some example 3d plots:

Example of rocks ejected from one position and their possible motions: https://dahlend.github.io/67p_beta_dust.html

Trying to determine possible orbits from a set of observations (the straight lines): https://dahlend.github.io/67p_dust_orbit.html

Shout out to pyvista for making these great 3d plots possible, a little less ergonomic than matplotlib, but it can export directly to html.
ddahlen
·10 months ago·discuss
Here you go, here is its orbit from 1900 to 2100 in the earth's rotating frame, sun is at -1 on the x axis.

https://dahlend.github.io/2025_PN7_Orbit_1900-2100.png

Its hanging out for a while near us.

Shameless plug for my software I used compute it:

https://github.com/dahlend/kete
ddahlen
·10 months ago·discuss
I made a 3D visualization of this a few weeks ago:

https://dahlend.github.io/the_belt.html

This includes about 1.3 million known asteroids (most of the known ones), so the page is like 45mb. Consider yourself warned.

This is a plot of semi major axis, orbital eccentricity, and inclination of the orbit. The blobs are collisional groups, where a bigger rock(s) got smashed into 'families' of asteroids. Color is by the absolute magnitude H, which is a normalized, log scaled, brightness measurement. Typically smaller H means larger object.

You can see the Kirkwood gaps clearly along one axis, but as you move around you can see more complex orbital resonances. These resonances pump energy into or out of the orbit of the asteroid, causing them to leave the resonance after some time, depleting the region of phase space.

Source: I do solar system simulations for my PhD work.
ddahlen
·10 months ago·discuss
One good reason to keep the raw data and orientation separate is hardware calibrations. I see some discussion here along the lines of "why not just flip the data before saving it", and one counter-argument is that you should store the flip metadata anyways, as it important to trace which hardware pixel corresponds to which stored pixel. I realize this information is not vital for everyone, but it is super useful in fields where you need to characterize the hardware performance at the pixel level (for example astronomy).
ddahlen
·10 months ago·discuss
There are quite a few open source projects in astronomy, but in my experience there is a tremendous amount of code that is squirrelled away as it is difficult to reproduce and entrenches peoples positions. I have mixed feelings about this in general, as I understand the incentive structures, but I do wish in general some of the sub fields were a bit more open. I do think things are getting better in general.

Also I fully agree with the "codes" rant.

Source: working professionally in the field for 4 years.